Reporter: Designer cosmetics cost a fortune. When I came across beauty blogs that said they found drugstore alternatives, you know I had to try them for myself. We start with a complexion enhancer. This one from benefit, cost $26. This one at target for $12. Lift up your cheekbone a little pit. Reporter: Let me look. Request not tell a difference. Reporter: Next, matte satin taupe eye shadows. This is the mac one. Sparkling. Reporter: Now, the l'oreal. That's so cool. I really like this one. Reporter: L'oreal, mac. I can't tell that much of a difference. Reporter: Now, a blush from nars. And the exact name of the shade. I don't think I can say that on national tv. And it cost $29. The knockoff is called milani and cost us just $7. This is gorgeous. Beautiful color. Okay. Now, we're going to try the milani. I have to add a lot more. Reporter: But 29 bucks for a blush, versus $7? I don't see that big of a difference. Finally, mac creme denude. 15. The other one made by elf. It's called natural nymph. Reporter: The elf seemed a little chalky. The knockoff loses for me here. One note, why not testing how the makeup wears. This is a looks-only comparison. But the makeup on this side of my face cost $33. And on this side, over $90. You decide for yourself. Glamming it up on the cheap, for "good morning america," becky worley, abc news, san francisco. I'm glad becky put that to the test for us. You can save money. And sometimes y splurge. Burning up on the "heat

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